Sustainability of layer housing systems examined

A group of scientific papers detailing the initial results of a broad study on several areas relating to the sustainability of three different commercial-scale egg production systems (conventional cage, enriched colony and cage-free aviary) is being published in the latest issue of Poultry Science, a journal of the Poultry Science Association (PSA). The research was conducted by the Coalition for a Sustainable Egg Supply (CSES), a multi-stakeholder group comprising more than two dozen members, including food manufacturers, research institutions, scientists, restaurants, food service and retail companies, egg suppliers, and nongovernmental organizations (NGOs).
“The goal of our project was not to make a determination that one type of layer housing system is better or worse than another. Rather, what we wanted to do was to provide some hard data to stakeholders on the tradeoffs between the different types of housing vis-à-vis key aspects of the sustainability of the entire egg production system. This will enable them to make better informed decisions with respect to questions concerning these systems – decisions that will no doubt reflect the specific values that they bring to this issue,” said Dr. Joy A. Mench, a professor of animal science at the University of California, Davis, and the co-scientific director of the project, along with Dr. Janice Swanson of Michigan State University.
The CSES research was facilitated by the Center for Food Integrity, a not-for-profit organization dedicated to building consumer trust and confidence in today’s food system by bringing together diverse stakeholders to address the issues most critical to consumers.
Areas of sustainability that were studied
The CSES project looked at the effects of the three housing systems on five areas related to a sustainable egg supply:


• Hen health and well-being
• Food safety and quality
• Environment
• Worker health and safety
• Food affordability
Nine papers from CSES detailing the first research results will appear in the latest issue of Poultry Science.  Additional results will be forthcoming, said Dr. Mench.
“To our knowledge this is the first time that all of the key aspects relating to egg production sustainability have been studied at the same time and at the same place.  Due to the growing importance of sustainability debates in our national conversation, we felt it made sense to present these initial findings together as a special section in a single issue of Poultry Science,” said Editor-in-Chief Dr. Tom E. Porter.
The nine papers, listed below, are available for download from Poultry Science:


• The Coalition for Sustainable Egg Supply project: An introduction (J.C. Swanson et al)
• Comparative evaluation of three egg production systems: Housing characteristics and management practices (Y. Zhao et al)
• Impact of commercial housing systems and nutrient and energy intake on laying hen performance and egg quality parameters (D.M. Karcher et al)
• Effect of rearing environment on bone growth of pullets (P. Regmi et al)
• An examination of the utility of heterophil-lymphocyte ratios in assessing stress of caged hens (Paul F. Cotter)
• Environmental assessment of three egg production systems–Part I: Monitoring system and indoor air Quality (Y. Zhao et al)
• Environmental assessment of three egg production systems—Part II. Ammonia, greenhouse gas, and particulate matter emissions (T.A. Shepherd et al)
• Microbiological impact of three commercial laying hen housing systems (D.R. Jones et al)
• Effects of housing system on the costs of commercial egg production (W.A. Matthews et al)